# Speed of disentanglement

1. Aug 7, 2005

### ACG

Speed of "disentanglement"

Hi! If two particles are entangled, A and B, and someone messes with A, have scientists determined the speed at which the "signal" that A has been messed with gets from A to B (so B reacts accordingly)? I read that they currently think it's infinitely fast and is permitted to exceed c because no information is transferred. However, at one point we thought light traveled infinitely fast as well. Have they actually proven that it's instantaneous (and if it is, in whose reference frame, if any)?

ACG

2. Aug 7, 2005

### DaTario

to the extent of my knowledge, entanglement is spoiled with a rate which is in general the highest rate appearing in the system. This in situations involving atoms implies the polarization decay rate which is somewhat near the classical time on one turn of the electron around the nucleus.

Best Regards

DaTario

3. Aug 7, 2005

### DrChinese

No upper limit has been discovered on the "speed of wave function collapse" for lack of a better term. No upper limit is anticipated, and this is not much of a burning question at this point. If you look at this well known experiment, they measure the value as about 10c in the reference frame of the light source.

Of course, there does not need to be any superluminal (FTL) action going on anyway. That is just one possible explanation of the facts, when you assume causes must precede effects or that there exist non-local hidden variables.